1. Technical Field
The embodiments described herein relate to a semiconductor integrated circuit (IC), and more particularly, to a device and a method for controlling a voltage of a semiconductor IC.
2. Related Art
Generally, a semiconductor IC commonly uses various internal power sources to drive devices within the semiconductor IC. The design of the semiconductor IC includes each internal power having a predetermined reference level. However, when the semiconductor IC is manufactured as an actual product after the circuit design is completed, the reference levels may be different from the reference levels set at the time of an initial design due to several factors during the manufacturing process. Thus, the semiconductor IC has been designed to include a device for controlling the internal power levels during the process of manufacturing the semiconductor IC.
FIG. 1 is a schematic block diagram of conventional device for controlling a voltage of a semiconductor IC. In FIG. 1, the device 1 includes first to fifth counters 11 to 15, first to fifth decoders 21 to 25, and first to fifth voltage controllers 31 to 35. The first to fifth counters 11 to 15 count first to fifth test signals ‘TM_VA’ to ‘TM_VE’ input in a pulse form, and output the counted values. The first to fifth decoders 21 to 25 decode the counted values to output first to fifth control step selection signals ‘SEL_A’ to ‘SEL_E’. The first to fifth voltage controllers 31 to 35 control first to fifth voltage VA to VE levels to meet the first to fifth control step selection signals ‘SEL_A’ to ‘SEL_E’.
The first to fifth test signals TM_VA to TM_VE in the pulse form can select the control step of the first to fifth voltages VA to VE according to their input frequency, wherein the control step for each input frequency of the first to fifth test signals ‘TM_VA’ to ‘TM_VE’ is previously defined. For example, when the first voltage VA is controlled among the first to fifth voltages VA to VE, the first test signal ‘TM_VA’ is generated by the frequency corresponding to the desired voltage control step. The first counter 11 counts the first test signal ‘TM_VA’, and outputs the counted value. The first decoder 21 decodes the counted value output from the first counter 11 to output the first control step selection signal ‘SEL_A’. The first voltage controller 31 controls the first voltage VA level to correspond to the first control step selection signal ‘SEL_A’.
Accordingly, the device 1 is configured to selectively control a plurality of internal voltages. However, the device 1 includes circuit components for controlling each of the internal voltages, such as a circuit for generating a test signal, a counter, and a decoder. Thus, the device 1 increases a circuit area, thereby decreasing a layout margin of the semiconductor IC. Correspondingly, the device 1 requires an increase in the number of signal lines for transferring signals between these components, thereby increasing the complexity of the circuit design.